The invention relates to a method of manufacturing a branched pipe.
The invention also relates to a pipe manufacturing apparatus, which comprises at least two sets of moving chill moulds, a mandrel arranged inside the chill moulds, at least one extruder for feeding plastic material into the mould defined by the chill moulds and the mandrel for manufacturing a manifold.
The invention further relates to a branched pipe comprising a manifold and at least one branch pipe.
A branched pipe, such as a bypass manifold or a branched pipe fitting, is typically manufactured from metal, such as brass, or from plastic by means of die-casting. This kind of manufacturing process of branched pipes is cyclical, the length of the articles is limited and as a result, the manufacture of branched pipes is rather expensive and laborious. There are also solutions which require either several single branches attached to one another or preferably a long pipe comprising several branches. Such solutions are needed e.g. in heat exchangers, in heating systems of sports grounds, in collectors of solar energy and in other corresponding solutions where several pipes are to be attached to a collecting pipe. Typically such branched pipes are made from an ordinary pipe to which a number of short pipes are welded, and pipes to be attached are welded or attached with a mechanical coupler to these short pipes. Such a branched pipe easily becomes very expensive since the welding of short pipes thereto is usually done manually. On the other hand, if for example T-branched pipe fittings are used for branching, the solution will be extremely expensive since there may be dozens or even hundreds of pipes to be attached.
The object of the present invention is to provide a branched pipe and a method and apparatus for the manufacture thereof, which allow to avoid the above-mentioned drawbacks.
The method of the invention is characterized in that plastic material is extruded into a mould defined at least by two sets of moving chill moulds and a mandrel arranged inside the chill moulds in such a manner that a manifold of a branched pipe is manufactured and the manifold of the branched pipe is provided with branch pipes simultaneously with the manufacture of the manifold.
The pipe manufacturing apparatus of the invention is further characterized in that the apparatus comprises heating means for the chill moulds and/or the mandrel arranged inside the chill moulds for heating the extruded plastic material above a melting point of the material and to a level required by crosslinking caused by heat.
The branched pipe of the invention is further characterized in that the manifold is manufactured by continuous extrusion and the branch pipe is arranged to the manifold in connection with the manufacture of the manifold.
The essential idea of the invention is that a manifold is manufactured by continuous extrusion by supplying the material to be extruded to the space defined by moving chill moulds and a mandrel arranged inside the chill moulds. Furthermore, the manifold is provided with branch pipes simultaneously with the extrusion thereof. The idea of a preferred embodiment is that the chill moulds are provided with branch pipe cavities for extruding the branch pipe simultaneously with the manifold and during the manufacture a branch pipe mandrel is arranged inside the branch pipe cavity so as to form a hole inside the branch pipe. The idea of another preferred embodiment is that prefabricated branch pipes are attached to a manifold during the manufacture thereof. The idea of a third preferred embodiment is that the branch pipes are made flexible.